ELECTRODEPOSITED TL2O3-MATRIX COMPOSITES I - EFFECT OF THE DISPERSED PHASE ON NUCLEATION AND GROWTH OF THE MATRIX

The electrodeposition of Tl2O3/Co3O4 composites has been performed by anodic oxidation of Tl+ ions in the presence of suspended Co3O4 partic les. This study, aimed at obtaining and characterizing new electrocata lytic materials for oxygen evolution reaction, has shown that Co3O4 pa rticles enhance the rate of nucleation and growth of the Tl2O3 matrix. At each potential, induction times are shorter and kinetic constants are higher in the presence of Co3O4 than in its absence. The chronoamp erometric transients measured during composite deposition are compatib le with instantaneous nucleation and 3D growth. Scanning electron micr oscopy and energy dispersive X-ray analyses data show that Co3O4 parti cles become effectively embedded in the deposit from the early stages of its formation and act as centers of preferential growth for the mat rix, so that the Co3O4 content is higher near the electrode/composite interface than in the bulk. Tl2O3/Co3O4 composites are compared with o ther systems for which nucleation and growth of the matrix is unaffect ed by the dispersed phase.